1. Field of the Invention
The present invention relates to a machine tool typified by a vertical lathe or an upright turning center in which vertical operation of a cross rail also occurs during machining.
2. Description of the Related Art
In such a machine tool, an entirely closed cover body enclosing a machining space around a turntable is traditionally provided in order to prevent coolant and swarf from being flung out during machining.
This type of machine tool is configured such that a tool post moves in a horizontal direction along a cross rail, and the tool post and the cross rail also move in a vertical direction along a column; therefore, the enclosure region of a machining space that is enclosed by a cover body changes. As a result, the cover body as shown, for example, in Japanese Patent Publication No. 5447931, is configured so as to keep the enclosure region sealed even when the enclosure region of the machining space is changed.
Japanese Patent Publication No. 5447931 relates to a cover structure for covering a machining space on a bed of a machine tool. Ceiling covers having an L shape in cross-section are provided to the right and left of the tool post, the ceiling covers comprising a vertical plate part having a front surface flush with the front surface of the tool post and a lower plate part having a lower surface flush with the lower surface of the tool post. A door and an upper edge of a front cover are bent rearward and come into contact with the vertical plate part of the ceiling covers. At least one of the ceiling covers is provided between a first sliding position adjacent to the tool post and a second sliding position set apart by a prescribed distance from the tool post, so as to be capable of sliding along the cross rail. A drive mechanism for causing the ceiling covers to slide as needed to the first and second slide positions is provided between the slidable ceiling covers and the tool post. The left and right of the tool post can be reliably closed off by the lower plate part of the ceiling cover, contact between the vertical plate part of the ceiling cover and the door is maintained even when the cross rail moves in the vertical direction, and the region above the machining space can be sealed. Furthermore, because the ceiling cover can be made to slide, a wide workpiece feed-in route can be ensured, and a workpiece can be fed in or out without interference from the ceiling cover.